Dry kiln



DRY KILN Filed June l, 1931 3 Sheets-Sheet 2 S14/vento@ g m/e/E; affe/'e/a am WWMMW Patented Sept. 29, 1.936

UNITED STATES PATENT OFFICE A'llIltY KILN Daniel R. Battenileld, Jacksonville, to Moore Dry Kiln Company,

Fla., assgnor Jacksonville,

Fla., a corporation of Florida Application June 1, 1931, Serial No. 541,468

'i Claims. (CL iid-46) The present invention relates to drying-kilns and more particularly to improvements in the construction and operation of kilns for drying An essential feature of the is to provide a drying kiln with present invention a continuous circulatingsystem for conducting the drying medium through a pile of lumber or other similar material, in which means are provided for dividing the stock load into separate circulating channels or passages that communicate with each other in such a manner that the drying medium circulates simultaneously in different directions through each load during the drying operation.

Another object of the invention consists in providing means for increasin g the velocity of the circulation through the load, said means also facilitating the drying of the lumber by dividing the kiln and load into circulating passages which extend in opposite directions, s

o that the drying medium is required to pass once through each of the passages of each load during its circuit of movement in the kiln. In other words substantially the entire volume of the arranged to rst pass through drying medium is a portion of the load in one direction and then through the remaining portion of the load in an opposite direction.

A further object is to provide a drying kiln with a delivery passage and a separate communieating suction passage through which the drying medium circulates in opposite directions in order that the circulation is balanced in the two parts of the load.

Another object is to provide ing a more uniform drying of the ends of the' means for insurlumber which normally .dry more rapidly than the intermediate portions thereof.

Another object of the linvention is to provide means which define circulating vchannels through substantially one half of the stock load or loads on the delivery side of the load and other circulating channels through the other portions of the load on the suction side thereof, whereby the drying medium circulates in opposite directions in the same loe-d and each circuit of circulationpasses once through each of the passages of each object of the invention is to provide transverse reversible circunce through each of the two passages of each load of lumber and limited circulation across the ends of the lumber.

A further object consists in the provision of means for producing alternate gravity circulation and forced air circulation respectively in diilerent parts of the stock load with each direc-v tion of circulation. 1

A further object of the invention is to provide a fan duct ,system for a drying kiln which system comprises a housing having mounted therein air l0 circulating means, the sides of the housing being formed with alternately opposed inlet and outlet openings for causing the air to be discharged from one side and sucked in from the other side during the drying operation of rthe system.

A still further object is to provide means in a fan circulating system for directing the circulation of the drying medium through the substance being dried and also means for reversing direction of the circulation after it has passed through the substance in such a manner that the drying medium will again pass through a portion of the substance before it is returned to the fan system.

Other objects and advantages of the invention will-become apparent from the following description taken in conjunction with the accompanying claims.

Referringto the drawings in which is disclosed a preferred embodiment of the invention:

Figure l is a sectional View taken substantially along the line l--i of Figure 2.

Figure 2 is a. sectional view taken substantially along the line 2--2 of Figure l.

Figure 3 is a sectional View taken substantially 35 along the line 3-3 of Figure 2.

Figure 4 is a detail perspective view of the fan housing. l Y

Referring to the drawings in which like numerals indicate like parts 'in the several views, 9 40 designates a kiln for drying material such as lumber or the like, which preferably is of elongated shape, but may be of any longitudinal and cross sectional dimensions so as to provide a drying chamber it for receiving the material to be treated.

The lower portion of the drying chamber is divided by the partition H into separate passageways l2 and i3. The partition Il extends longitudinally the full length of the kiln and terminates at a point adjacent the upper surface of the transverse I-beams i4. The beams i4 are suit-w ably spaced from one another and preferably are embedded in the sides I5 of the kiln and act as' supports for the tracks I6 which carry the wheel 55 trucks or bunks n on which is mounted the stock .load of lumber I8 or other material to be introduced into the drying chamber I for treatment. Each end of the kiln has a pair of doors I6 and 23 hinged as at 2I to the sides of the kiln to provide inlet and outlet openings for the introduction and withdrawal of the load I8 to the drying chamber.

The lumber I6 is piled` on each of the trucks I1, preferably on edge but may be stacked in any other preferred manner. The layers of boards of the stock load are spaced apart by suitable stickers 22 (Fig. 3), preferably placed vertically between the layers of lumber to provide passages or interstices 23 and 24 on opposite sides of the medially disposed stickers 22 for permitting air circulation through the load. As shown, the stickers 22 are arranged in rows, one row preferably at each end ofthe stock load and the intermediate row or rows preferably located at or near the center of the load to divide the passages 23 and 24 into air delivery channels and suction channels of circulation that are spaced from each other by the centrally disposed row of stickers 22. The stickers 22 are preferably made of lumber, and in some cases may be formed'of one of the boards to be treated. or may be made speciilcally for the purpose of spacing the layers and used over and over again in successive loads. In

some cases the stickers 22, which are a constituent part of each load, are division members for passage of air circulation, and in other cases layers of lumber are division members for passages of air circulation through the stock loads.

As illustrated, the stock loads of material to be dried are preferably composed of individual boards of lumber horizontally stacked in layers and spaced apart preferably by the transversely placed stickers 22 so that each load contains boards lwhich extend substantially its full length. The load preferably is maintained firmly in position on each of the trucks I1 by the standards 2l, the lower ends of which nt in the sockets 26 formed in the bottom of the truck. The standards 26 are arranged in opposed pairs that may have their upper ends connected by the exible binders or straps 21 (Fig. 3), so that when the lumber is positioned between the standards and the binders moved to force the upper ends of the opposed standards together, the lumber will assume a compact form. Heating coils 26 are positioned beneath the stock load at a point to be in the path of maximum air circulation and may be supported or suspended from the I-beams I4. Additionally, heating pipes 23 may be positioned in the chamber III above the load, to insure further heating of the air or treating medium as it issues from either the passage 23 or 24, depending upon the direction of circulation of the air.

It will be noted that the partition II is arranged in substantial augment with a partition comprising the medial row or stickers 22 (Fig. 1), which preferably are a constituent part of the lumber to constitute means dividing the lower portion of the drying chamber and the stock load of lumber into separate air circulating channels comprising the aligned passages I3 and 23 on one side and the aligned passages I2 and 24 on the other side thereof.

Transverse circulation of the air or other heat- Ing medium through the chamber I0 preferably is effected bylmeans of the two sets of fans 33 and 3| which extend longitudinally of the kiln and are positioned within a housing 32, one of the side walls of which is formed by the partition II (Fig. l). The fans 30 and 3i are keyed or otherwise secured to a reversible drive shaft 33 which extends longitudinally of the chamber 'I0 and may be connected to a motor or the like, not shown, in any well known manner. The shaft 33 is revolubly supported by the standards v34% secured to the bottom of the kiln. The fans 30 are preferably right hand and are arranged in series on one side of the shaft 33, while the fans 3i are preferably left hand and are arranged in vseries on the other side of the shaft, so as to neutralize end thrust and equalize the distribution of circulation of the air Within the kiln. Obviously, the fans may be all of the same pitch or may be arranged in opposed vpairs to discharge air in \counteracting currents; in fact any desired arrangement of the fans may be employed for producing continuous transverse circulation through the load. l

The housing 32 is divided by the vertical walls 36 into a series of separate sections or compartments in each of which is mounted one of the fans to divide the same into sub-compartments 36 and 31 that will be referred to as air delivery compartments and suction compartments for eiIecting continuous transverse air circulation in the kiln (Fig. 2). It will be noted that the compartments 36 and 31 are alternatively disposed on opposite sides of the fans and extend substantially the full length of the drying chamber. As the direction of rotation of the fans 30 and 3i is reversible, it will be seen that the terms "air delivery compartment" and "suction compartment, are used in a relative sense, depending upon the direction of circulation of the fans.

The housing 32 which constitutes the fan system is deilned by the bottom of the kiln I0, the partition II on one side, a wall 38 on the opposite side, and a top wall 33, the sections being divided into the various compartments by the cross walls 33, so as to constitute ilve closed sides for each of the compartments 36 and 31.

The top wall 39 of the housing 32 is provided with spaced opening 40, which are arranged to communicate the compartment 36 with the passage I3, while the side wall II of the housing has a series of spaced openings onset relative to the openings 40, so as to establish comunication between the'compartments 31 and the passage I3. It will be seen that upon the rotation of the fans 30 and 3'I in a counter-clockwise direction, as indicated by the arrows in Figure 1, communication is established between the compartments 36 and 31 of each of the sections to effect continuous circulation of the air within the kiln, the air being drawn in from the passages I2 and 24 through the openings 4I to each of the compartments 31 and carried over to the compartment 36 from where it is forced through the openings 40 to the passages I3-and 23 respectively. By providing means simultaneously directing the air in opposite directions through the load, the main volume of air passes the same footage of lumber in both directions, thus insuring an even and uniform drying thereof.

'I'he openings 40 and 4I in each of the compartments 36 and 31 are preferably provided with flexible baiiles 42 and 43 respectively, which may be adjusted by flexion for directing the circulation transversely within the kiln. The medial partition 35 (Fig. 2) may also be formed with the substantially Y-shaped baffles 44 for deilecting the air in the desired direction. While the vertical walls 35 that separate the housing into the vari- I to the air discharge from the fans, it is obvious that they may be arranged at any desired angle, since in some cases it is preferable to change the angle of the walls 35 to provide a freer discharge from the fans in both directions of circulation.

Fresh air conduits 45 and 48 extend longitudinally of the bottom of the kiln on opposite sides of the'fan housing 32, and are opened at one end of the kiln by the doors 41 (Fig. 3) to control the volume of fresh air delivered to the drying chamber. The conduit 45 is located on the left hand side of the kiln and is used when the circulation is moving from the passageway I2 into the housing 32 and being forced upwardly through the passageway I3. The passageway 43 is located on the right hand side ofthe kiln and communicates with each of the compartments 31 through the small conduits 48 (Fig. 3). The openings 49 and 50 in the conduits 45 and 46, may be provided with louvers I and 52 respectively, (Fig. 1), for permitting control of the fresh air delivered into the kiln.

Spray pipes 53 may be positioned within the y heating chamber for the release of live steam to humidity the air within the kiln. Ventilators 54 are positioned in the top of the kiln to supply the kiln with the desired amount of excess moisture. The ventilators are so positioned that the air will be exhausted from the kiln after it has passed at least once through the stock load I8, thus increasing the eiilciency of the kiln and reducing the steam consumption.

Bafes 55 extend from the top of the kiln to a point adjacent the upper adjacent ends of the load, while laterally disposed bailies 56 project from the sides of the kiln adjacent the lower ends of the load, so as to provide means to prevent the air from evading the load and also to protect the ends of the stock by reducing the circulation across the ends of the load. u

In operation the load of lumber i3 or other material to be dried, is rst placed on the wheel trucks il with the lumber piled edge to edge and the layers spaced by the stickers, so as to provide the spaced air circulating passages 23 and 2li in the load. The trucks are then rolled on the tracks i5 into the kiln through the doors I9 so as to assume a position in which the central stickers 22 form a continuation of the partition wall I I, so that one side of the heating chamber,.assuming that the fans are rotated in a counter-clockwise direction, provides an ascending air circulating passage formed by the passages I3 and 23, while the other side constitutes a descending passage formed by the passages I2 and 24. The fresh air or heating medium introduced into the kiln through the conduit 45 is drawn in through the openings 4I of the compartments 3l into the heusing 32 and is forced upwardly through the openings 40 in the compartments 35 so as to iirst pass the heating coils 23 and then through the passages 23 of the load. The air is then deflected across the top of the load past the heating coils 2S and is drawn downwardly through the passages 24 and l2 by the suction of the fans. It will, therefore, be seen that in each circulation of movement the air in the kiln illustrated passes upwardly through one part of the load and downwardly through the other part thereof, so as to pass twice through each load during its circuit of movement. Y

Upon reversing the direction oi! rotation of the fans, that is to say, upon the fan revolving in a clockwise direction, the circulation of the air through the kiln is reversed.,

It will be seen that -by reason of separating the load on each of the trucks I1 into separate passages by the medial stickers 22, that the air circulates simultaneously in opposite directions on opposite sides of the load, thus increasing its velocity and facilitating the drying operation. On reversal of circulation of the air by rotation of the fans in a clockwise direction, that part of' the load which had upward circulation against the force ot gravity and a downward circulation with the force of gravity is automatically reversed, so that the part of the load that has the gravity circulation then loses its gravity eiect and the side of the load which would not have the gravity circulation gains the same. It is by reason of the reversal of circulationthat the force of gravity acts alternatively on the diierent parts of the same load or associated loads for produc- -ing a greater uniformity in drying. Moreover,

as the air delivery circulation and suction circulation act separately on two parts of the same load at the same time, they co-act to balance the'circulation' in the two parts of the load.

It will be seen that in operation the circulation is alternatively aided by gravity in passing through one part of the stock load in either direction for circulation. Consequently, at the beginning oi.' the drying period there is a greater gravity circulation through the load than at the end of the drying period. The gravity circula-l tion tendency in one part of the load materially aids the fan circulation in producing an upward circulation in a dierent part. of the load. To-

Wards the end of the drying process the gravity circulation is diminished, but the gravity circulation rate is lower and the dry atmosphere is easily forced through the interstices or passages 23 and 24 of the load, so that at the beginning of the drying process the gravity circulation aids in effecting uniform circulation and at the end of the drying period the fans more easily force circulation through the lumber or the like.

Obviously, the fans and their associated parts instead of being placed below the stock load as shown, may be located above the stock load which would merely involve the inverting o the kiln as shown in Figure l. Moreover, the ian circulating system can equally well be placed on either side of the load which would diier from the present disclosure in that the adjacent layers of lumber would be separated by horizontally disposed stickers or spacing means so that the air circulation would be horizontal through the stock load instead of vertical. When the fan circulating system is positioned above or in the outside wall of the kiln, the fresh air ducts 45 and i6 would be eliminated as the fresh air would deliver to the heating chamber through suitable openings formed in the walls of the fan housing. in this construction also, the fresh air ports 45 and 46, and the ventilators 54 would be in eiect transposed at each reversal of circulation, since the ports on the suction side of the housing for the fan would act as fresh air ports and those on the delivery side would function as ventilators.

It is to be understood that the form of the invention herewith shown and described is merely illustrative of a preferred embodiment and that s uch changes may be made as fall within the purview of one skilled in the art without departing from the spirit of the invention and the scope of the appended claims.

I claim:-

1. The method of drying lumber which consists in providing a pile of lumber piled in spaced 'nsA courses in'to two parts having substantially completely separated passages disposed transversely oi' the length of the lumber, and passing a heating medium in one direction through the 'passages in one part of the pile of lumber and ln the opposite direction through the passages in the other part of the same pile of lumber.

2. A drying kiln o! the class described including a drying chamber, a housing extending longitudinally oi'. the chamber and having an 'upwardly projecting side dividing one portion of the chamber into separate passages, a track in said kiln arranged to receive a lumber stock load, the lumber stock load being movable on said track to assume a position adjacent to the housing, means in alignment with said upwardly projecting side for separating the load into spaced layers providing two separated passages forming a continuation of the passages within the kiln, means for introducing fresh air into said kiln, and reversible fans operatively mounted in said housing for effecting the circulation of the air simultaneously in opposite directions through the two passages of'said load.

3. A drying kiln of the class described including-a drying chamber, a housing extending 1ongitudinally of the chamber and having an upwardly projecting side separating the lower portion of the chamber into separate passages, a track in said kiln arranged to' receive a stock load of lumber, the stock lo'ad being movable on said track toI assume a position immediately above the housing, means providing circulating passages in the stock load, said means separating the load medially into a continuous circuit havingpassages extending in opposite directions and communicating with the passages in said kiln, a series oi' fans revolubly mounted in said housing ior eiIecting circulation of the drying medium through said circuit whereby the drying medium passes in opposite directions twice through each load in each circuit of movement, and means in said kiln adjacent the ends of the load for reducing the circulation oi the drying medium at said ends.

4. A drying kiln of the class described including a drying chamber, a housing extending longitudinally of the chamber and' having an upwardly projecting side separating the lower portion of the chamber into separate passages, a track in said kiln arranged to receive a stock load of lumber, the stock load being movable on said track to assume a position immediately above the housing, vertically disposed stickers separating the load into circulating passages, said stickers being positioned in substantial alignment with the projecting portion of the side of the housing whereby to divide the kiln and the load into a delivery passage and'a suction passage extending in opposite directions, means for introducing a drying medium into said kiln, fans revolubly mounted in said housing, said housing having openings in din'erent sides thereof whereby to effect circulation twice through the stock load in each circuit of movement.

5. A drying kiln of the class` described including s, drying chamber, a housing extending longitudinally of the chamber and having an upwardly projecting side separating the lower portion of the chamber into separate passages, a track in said kiln arranged to receive a stock load of lumber, the stock load being movable on said track to assume a position immediately above the housing, vertically disposed stickers separating the load into circulating passages, said stickers being positioned in substantial alignment with the projecting portion of the side of the housing whereby to divide the kiln and the load' into a delivery passage and a suction passage extending in opposite directions, means for introducing a drying medium into said kiln; fans revolubly mounted in said housing, said housing having spaced vertically disposed partitions providing separate compartments, a fan revolubly mounted in each of said compartments and dividing the same into subcompartments having openings in diierent walls thereof which communicate respectively with the passages in the lower portion of the chamber whereby to eiIect circulation twice through the stock load in each circuit of movement.

6. The method of drying lumber which consists in dividing a pile of lumber piled in spaced courses into two substantially, completely separated halves and passing air in one direction through one half of the pile of boards and in the opposite direction through the other half of the same pile of boards.

7. A dry kiln having a lumber stock load therein, said load comprising boards arranged edge to edge in layers, a row of stickers separating the layers, the medial stickers providing two circulating passages for each layer, one a delivery passage and the other a suction passage, each of said passages extending across substantially one-half the length oi' the load, said kiln having a partition member in alignment. with said stickers, a Ian positioned within the kiln and communicating with said passages, whereby to eilect transverse circulation through one passage of the lumber in one direction and through the other passage in the opposite direction.

Y DANIEL R. BA'I'I'ENFIEID. 

